1. Section 2: Isotopes and Radioactive Elements
Lesson 15 Nuclear Quest
Lesson 16 Old Gold

2. Lesson 15: Nuclear Quest
Nuclear Reactions

3. ChemCatalyst
Using the Nuclear Quest game, find the ten kinds of cards shown below. Which cards cause the nucleus of one element to change into the nucleus of a different element?

4. Key Question
What are nuclear reactions?

5. You will be able to:
explain the different processes involved in nuclear changes and the conditions required for those processes
explain the connection between nuclear changes and changes in atomic identity

6. Prepare for the Activity
Work in groups of four.
The goal of the game is to discover element 112 and name it. This is accomplished by moving the nucleus through the entire periodic table.

7. Discussion Notes
Alpha Decay

8. Discussion Notes (cont.)
Beta Decay

9. Discussion Notes (cont.)
Nuclear chemistry is the study of changes to the nucleus.
Nuclear reaction: A process that involves changes to the nucleus of an atom.
Radioactive decay: A spontaneous process by which an atom emits radiation or a particle from its nucleus to become more stable.
Fusion: The joining of two nuclei to form a larger nucleus accompanied by a release of energy.
Fission: The splitting apart of an atomic nucleus into two smaller nuclei accompanied by a release of energy.

10. Discussion Notes (cont.)
Changes in the nucleus of an atom can change the identity of an element.
Alpha particle: A particle composed of two protons and two neutrons, equivalent to the nucleus of a helium atom.
Beta particle: An electron emitted from the nucleus of an atom during beta decay.
Gamma ray: A form of high-energy electromagnetic radiation emitted during nuclear reactions.

11. Discussion Notes (cont.)
Nuclear changes frequently involve the transfer of large amounts of energy.
Alpha decay: A nuclear reaction in which an atom emits an alpha particle. Its atomic number decreases by 2, and its mass number decreases by 4.
Beta decay: A nuclear reaction in which a neutron changes into a proton, and the atom emits a beta particle. The atom’s atomic number increases by 1.

12. Wrap Up What are nuclear reactions?
Alpha decay results in a decrease in the atomic number by 2.
Beta decay results in an increase in the atomic number by 1.
Gamma radiation usually accompanies alpha and beta decay and also fission. Gamma radiation can be quite harmful to humans.

13. Wrap Up (cont.)
Nuclear fission involves a single nucleus breaking apart into two smaller nuclei.
Nuclear fusion involves two nuclei combining to form a nucleus with a larger atomic number. Nuclear fusion takes place in extremely hot environments, such as the cores of stars.

14. Lesson 16: Old Gold
Formation of Elements

15. ChemCatalyst 1. What patterns do you notice in the fusion reactions?
2. Do you think gold can be created on Earth by a fusion reaction? Explain your thinking.

16. Key Question
How are new elements formed?

17. You will be able to:
explain how different elements are formed through nuclear reactions
write a balanced nuclear equation
describe the mechanism behind a nuclear chain reaction

18. Prepare for the Activity
Work individually.
You will need a copy of the periodic table and the isotope chart from Lesson 14.

19. Discussion Notes
Nuclear processes can be written as nuclear equations.
During alpha decay, the nucleus of an atom emits a helium nucleus, transforming the element into an element with a smaller nucleus.
During beta decay, a neutron inside the nucleus of an atom emits an electron.

20. Discussion Notes (cont.)
Nuclear fusion involves the joining together of nuclei.
Fission involves a nucleus breaking up into smaller nuclei.
Nuclear reactions change the identity of an element.
Nuclear fusion produces bigger (heavier) elements from smaller (lighter) ones.

21. Question 5
____ β Ca ____ 42He Ra 23892U _____ La

22. Discussion Notes Ca Sc  g + U Th 
Nuclear processes can be written as nuclear equations.
Beta particle Ca 47 20 Sc 21  g + U
238 92 Th
234 90 
Alpha particle

23. Discussion Notes (cont.)
Nuclear Chain Reactions

24. Discussion Notes (cont.)
Nuclear fission is a process that releases enormous amounts of energy.
Nuclear fission can result in a nuclear chain reaction that produces a great deal of energy.

25. Discussion Notes (cont.)
Fission = nucleus breaking up into smaller nuclei.
Nuclear reactions change the identity of an element.
Starting isotope = parent isotope
Resulting isotope = daughter isotope
Nuclear fusion = produces bigger (heavier) elements from smaller (lighter) ones.

26. Nuclear Equations for Fusion
42He + 42He 84Be 84Be + 42He 126C 126C + 42He 168O
Do you think gold can be created on earth by a fusion reaction? Explain your thinking.

27. γ +2 (no electrons) 0-1e, β -1 Name Particle Charge
Penetrating Ability
Alpha (helium nucleus)
42He, α
+2 (no electrons)
Weak, can be stopped by paper or skin
Beta (high energy electron)
0-1e, β -1
Moderate, Can be stopped by wood, aluminum foil
Gamma (high energy photons) γ
High, can only be stopped by lead or thick concrete

28. Writing an equation for alpha decay
23892U α Th Nucleus emits an alpha particle, transforming it into a smaller nucleus the greek letter α is used to represent a helium nucleus

29. Writing an equation for beta decay
10n 0-1e + 11p a neutron splits into an electron and a proton 14056Ba β La The mass remains the same

30. Writing an equation for fission and fusion
5224Cr + 42He 5626Fe Fusion involves the joining together two nuclei 23592U 14156Ba Kr + 10n + 10n Fission involves a nucleus breaking up into smaller nuclei

31. Wrap Up How are new elements formed?
Radioactive decay, nuclear fusion, and nuclear fission are all nuclear processes that result in the creation of new elements.
The mass of a nucleus changes when neutrons or protons are added or lost.
The identity of an element changes when its nucleus gains or loses protons.

32. Wrap Up (cont.)
Radioactive decay happens in the natural world around us. Fission can be spontaneous for unstable nuclei, or it can be provoked using nuclear bombardment and other methods. Fusion of nuclei to form different isotopes happens in the stars.

33. Check-in In a paragraph, defend this statement:
If you want to find gold, your best bet is to dig “old” gold out of the ground. Your chances of making “new” gold are slim.